1. Technical Field
The present invention relates to a method and apparatus for controlling operation of a redox flow battery.
2. Description of the Related Art
A redox flow battery refers to an electrochemical electricity storage device which charges or discharges electricity through oxidation/reduction of ions contained in an electrolyte. In such a redox flow battery, an anolyte and a catholyte composed of different kinds of active materials are separated from each other by a separator.
Ion crossover occurs through the separator and the amount of ions exchanged through the separator varies according to the kind of active material, that is, the oxidation number of ions, so that the amount of one of the catholyte and the anolyte increases. Such unbalanced crossover breaks a capacitive balance between the catholyte and the anolyte and reduces use rate of electrolyte solutions, thereby causing reduction in capacity of the battery.
To solve the problem of capacity reduction of the redox flow battery, a method of mixing the anolyte and the catholyte or a method of migrating one of the electrolyte solutions from one storage tank to another storage tank containing the other electrolyte solution is used in the related art. However, mixing or migration of the electrolyte solutions requires a separate energy source and a considerable time in solving the problem of capacity reduction. Moreover, the method of mixing the electrolyte solutions under certain conditions has a drawback of consumption of energy charged in the battery.